1. Field of the Invention
The present invention relates to a photosensitive resin composition useful for forming protective films such as insulating protective films for use in semiconductor elements, oriented films for use in liquid crystal display elements, and insulating films for use in multi-layered printed circuit boads, and to a process for forming a patterned polyimide film using said composition.
2. Description of the Prior Art
As conventional heat resistant photosensitive materials, there are known, for example, a material comprised of polyamic acid and bichromic acid salt (Japanese Patent Publication (Kokoku) No. 49-7374 corresponding to U.S. Pat. No. 3,623,870, GB 1316976 and CA 918484), a material prepared by introducing a photosensitive group into the carboxyl group of polyamic acid with the aid of an ester bond (Japanese Pre-examination Patent Publication (Kokai) No. 49-115541 and Japanese Pre-examination Patent Publication (Kokai) No. 55-45746, which correspond to U.S. Pat. No. 3,957,512 and GB 1467226), a material comprised of polyamic acid and a amine compound having a photosensitive group (Japanese Pre-examination Patent Publication (Kokai) No. 54-145794 corresponding to U.S. Pat. No. 4,243,743), and a material prepared by introducing a photosensitive group into the carboxyl group of polyamic acid with the aid of an silylester bond (Japanese Pre-examination Patent Publication (Kokai) No. 62-275129).
These photosensitive materials, however, should use, as a liquid developer, an organic solvent when developing. The use of the organic solvent involves the problems such as an affect on the operator's health and the treatment of waste liquids.
In order to solve the above problems, there have been proposed as a photosensitive material capable of developing with an aqueous liquid, for example, a material comprised of a substance prepared by introducing a photosensitive group into the carboxyl group of polyamic acid with the aid of an amide bond (Japanese Pre-examination Patent Publication (Kokai) No. 60-100143 and Japanese Pre-examination Patent Publication (Kokai) No. 2-157845, which correspond to U.S. Pat. No. 4,515,887, U.S. Pat. No. 4,587,204 and GB 2145728), a positive type photosensitive composition prepared by mixing a polyimide resin having a phenol group with naphthoquinonediazidesulfonic acid ester (Polymer Engineering and Science, July 1989, Vol. 29, 954).
These photosensitive materials, however, involve the problems that they require a long time to develop and can not exhibit a sufficient sensitivity especially when formed into a thick film.